Hi, hmmm. I think about write I/O. Even if SAPDB is smart, it cannot prevent to issue two system calls instead of a single system call. The Linux kernel can save you thereby one system call overhead at least.
But i still prefer hardware Raid0, since if it is intelligent made, it reduces the overhead to a single I/O, thereby reducing the bus load. A software solution with separate disk is more flexible, but since the disks does not know what you want to do, even the Linux kernel has to transfer data twice. CU jrg > -----Original Message----- > From: Flemming Frandsen [mailto:[EMAIL PROTECTED] > Sent: Montag, 31. M�rz 2003 18:13 > To: SAPDB > Subject: Logging to a mirror vs. LOG_MODE DUAL > > > I'm setting up a new system here and I want to get the best possible > performance, the platform is Linux 2.4.18 (SuSE 8.1) and I > have two fast > disks for putting the log on, but how? > > Option 1: Create a mirror of the two devices and use the > mirror in raw > mode as a single log device (LOG_MODE SINGLE) > > Option 2: Create two raw devices and let SAP DB use them in > LOG_MODE DUAL. > > Is SAP DB smart about what data it reads from the two disks > or will I be > better of letting the OS handle the mirroring? > > -- > Regards Flemming Frandsen - http://dion.swamp.dk > PartyTicket.Net co founder & Yet Another Perl Hacker > > _______________________________________________ > sapdb.general mailing list > [EMAIL PROTECTED] > http://listserv.sap.com/mailman/listinfo/sapdb.general > _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general
